Purpose: Practitioners must have confidence in the capacity of their language measures to discriminate developmental language disorders from typical development and from other common disorders. In this study, psycholinguistic profiles were collected from 3 groups: children with specific language impairment (SLI), children with attention-deficit/hyperactivity disorder (ADHD), and children with typical development (TD). The capacity of different language indices to successfully discriminate SLI cases from TD and ADHD cases was examined through response operating characteristics curves, likelihood ratios, and binary logistic regression. Method: The Test of Early Grammatical Impairment (Rice & Wexler, 2001a), Dollaghan and Campbell's (1998) nonword repetition task, Redmond's (2005) sentence recall task, and the Test of Narrative Language (Gillam & Pearson, 2004) were administered to 60 children (7-8 years of age). Results: Diagnostic accuracy was high for all 4 psycholinguistic measures, although modest reductions were observed with the SLI versus ADHD discriminations. Classification accuracy associated with using the Test of Early Grammatical Impairment and the Sentence Recall task was equivalent to using all 4 measures. Implications: Outcomes confirmed and extended previous investigations, documenting high levels of diagnostic integrity for these particular indices and supporting their incorporation into eligibility decisions, differential diagnosis, and the identification of comorbidity.